“Hard copy” print media such as paperback books have a number of advantages over electronic publications. Some electronic books, for example, can be read using a device such as a personal digital assistant (PDA). However, the screens of PDAs are very small and it can be difficult to read the text of books on the PDAs. Moreover, it is difficult to manipulate the pages of an electronic book as a user must scroll through a number of pages to get to a page of interest. It is often faster for the user to turn a page of an ordinary book to quickly get to the desired page. Because the pages of an ordinary book can be turned quickly, the user can understand the context of a story or article that occupies many pages of the book much more quickly than would otherwise be the case when turning the pages of an electronic book. Furthermore, although improvements have been made to electronic display screens in recent years, printed matter on paper is often easier for people to read than electronic print on an electronic display screen. For instance, glare on an electronic display screen can make an electronic book difficult to read. Paper, on the other hand, typically does not produce excessive glare. Lastly, although sales of electronic publications are increasing, sales of traditional print media remain very high indicating a continuing consumer preference for hard copy print media. One reason for this may be that traditional print media are typically easier to use than electronic print media.
Although hard copy printed media have many advantages over electronic publications, hard copy printed media have a number of limitations. For example, the information which can be present in a hard copy printed medium such as a magazine is limited to the number of pages within it. If the reader wants additional information about a particular subject being read, the reader must take the time search for the information. For example, if a reader wants more information about a product in a story or an advertisement that he or she sees in a magazine, the reader must take affirmative steps to locate the additional information. The reader can contact the seller of the product by mail, phone or the Internet to obtain additional information about the particular product advertised. The additional effort undertaken by the reader is very inconvenient to the reader. Moreover, the retrieval of the additional information is delayed by the time needed to determine how to obtain the information as well as the time needed to actually obtain the information.
To address this problem, some have suggested printing specialized machine readable codes such as barcodes or digital watermarks containing embedded information of a uniform resource locator (URL) on the pages of a print medium such as a magazine. The barcodes or watermarks can then be scanned using a scanner and a computer can obtain auxiliary information from the Internet using the URL.
Printing many specialized machine readable codes such as multiple barcodes or digital watermarks on a print medium such as a magazine, however, has a number of disadvantages. For example, having many barcodes or watermarks in a print medium makes the printing process for the particular print medium more difficult and more expensive. The increased cost will likely deter many publishers from printing many the machine readable codes in their publications. Moreover, the visual appearance of a print medium is significantly compromised when the print medium includes multiple barcodes. Pages of a magazine, for instance, appear cluttered to a reader and thus less visually pleasing when many barcodes are present. Furthermore, if the barcodes or watermarks are blurred in some manner in the printing process, the scanner may not be able to scan the barcode and obtain the auxiliary information.
Embodiments of the invention address these and other problems.